Melatonin for Sleep: What the Research Says, and What Is in the Bottle

Melatonin is a hormone your body makes, and it is also sold as a supplement. What the research supports depends on which problem you are asking about. This guide sets out what pooled studies and clinical guidelines say, where melatonin has a better case, what the safety sources warn about, and a finding most guides skip: what is in the bottle does not always match the label.

It is not medical advice. If sleep trouble is persistent, talk to a healthcare provider.

The Short Answer

For people with primary sleep disorders, pooled trials show a small average effect. In a meta-analysis of 19 studies, melatonin shortened the time to fall asleep by about 7 minutes and lengthened total sleep time by about 8 minutes. The authors call the effects modest.
For chronic insomnia in adults, the American Academy of Sleep Medicine (AASM) suggests clinicians not use melatonin. It is a weak recommendation from 2017, resting on very low quality evidence. NCCIH adds that the American College of Physicians (2016) also found too little strong evidence to recommend it, and that the ACP strongly recommends cognitive behavioral therapy for insomnia (CBT-I) as the first step.
The case is better for timing problems, such as jet lag and delayed sleep-wake phase disorder, though the evidence is still limited.
Short-term use appears safe for most people, according to NCCIH, and information on long-term safety is lacking. People with epilepsy or on blood thinners need medical supervision, and there is little research in pregnancy.
The amount in a supplement can differ sharply from the label. A 2017 test of 31 supplements found melatonin from 83% below to 478% above the labeled amount. A 2023 test of 25 gummy products found 22 inaccurately labeled.

What the Pooled Studies Show

Ferracioli-Oda and colleagues, 2013. This meta-analysis pooled 19 placebo-controlled studies with 1,683 adults and children who had primary sleep disorders. Melatonin shortened the time to fall asleep by about 7 minutes (95% CI 4.4 to 9.8) and lengthened total sleep time by about 8 minutes (95% CI 1.7 to 14.8). Overall sleep quality improved by a standardized mean difference of 0.22. The authors call the effects modest, note that they did not appear to fade with continued use, and say the absolute benefit is smaller than that of other drugs used for insomnia. Longer trials showed larger effects on both the time to fall asleep and total sleep time, and higher doses showed larger effects on total sleep time and, at trend level, on the time to fall asleep. Neither dose nor duration made a significant difference to sleep quality (PubMed).

Gholami and colleagues, 2022. This meta-analysis of 23 randomized trials, drawn from 2,642 papers, looked at adults with various diseases and measured sleep quality on the Pittsburgh Sleep Quality Index. Melatonin improved scores in adults with respiratory diseases, metabolic disorders and primary sleep disorders, and not in those with mental disorders, neurodegenerative diseases and other diseases (PubMed).

Poza and colleagues, 2022. A review from the Spanish Sleep Society’s insomnia study group says that, despite the theoretical appeal of replacing the melatonin that declines with age, little scientific evidence supports any benefit from that approach, and that the most suitable doses and preparations are still to be clearly defined (PubMed).

What the Guidelines Say

AASM, 2017. In its guideline on medications for chronic insomnia in adults, the AASM task force issued Recommendation 12: it suggests that clinicians not use melatonin for sleep onset or sleep maintenance insomnia in adults. The recommendation is weak. It rests on three trials of 2 mg prolonged-release melatonin, all in adults over 55, and the guideline rates the overall quality of evidence as very low. The one meta-analysis possible, on sleep quality, gave a standardized mean difference of +0.21 with a confidence interval from −0.36 to +0.77, which the task force called not clinically significant. It found no adequate data on side effects and judged the benefits to be about equal to the harms. It also noted that most well-informed patients would choose melatonin over taking nothing, because it is widely available and widely seen as a benign sleep aid (JCSM).

AASM, 2026. The AASM’s newer guideline on combining CBT-I with insomnia medication recaps the 2017 guideline, including its conditional recommendations against several agents, melatonin among them (JCSM).

NCCIH’s summary of the guidelines. The U.S. National Center for Complementary and Integrative Health says the AASM (2017) and ACP (2016) practice guidelines found not enough strong evidence on the effectiveness or safety of melatonin for chronic insomnia to recommend its use, and that the ACP strongly recommends CBT-I as the first step (NCCIH).

Where the Case Is Better: Timing Problems

NCCIH separates chronic insomnia from problems of sleep timing:

Jet lag. Research suggests melatonin may help. Four studies with a total of 142 travelers showed it may be better than a placebo at reducing overall jet lag symptoms after eastward flights.
Delayed sleep-wake phase disorder, in which a person cannot fall asleep at usual times. Melatonin appears to help with sleep, but it is uncertain whether the benefits outweigh the possible harms. The AASM recommended it given at specific times in 2015, as a weak recommendation.
Shift work. Two 2014 reviews found the studies generally small or inconclusive.

Safety

NCCIH, in a page last updated in May 2024, says:

Short-term use of melatonin supplements appears to be safe for most people. Information on long-term safety is lacking, and for doses higher than the body normally produces there is not enough information on side effects to give a clear picture.
Mild side effects reported in short-term studies included headache, dizziness, nausea and sleepiness. There may be a risk of allergic reactions.
People with epilepsy and people taking blood thinners need to be under medical supervision if they take melatonin, and anyone taking medicine should consult a healthcare provider first.
There has been a lack of research on melatonin in pregnant or breastfeeding women.
Parents considering melatonin for a child should speak with a healthcare provider first. Because melatonin is a hormone, NCCIH says it is possible that it could affect hormonal development, but this is not known for sure.

What Is Actually in the Bottle

In the United States, melatonin is sold as a dietary supplement, which NCCIH notes means the FDA regulates it less strictly than a prescription or over-the-counter drug. Two studies measured what products actually contained.

Erland and Saxena, 2017. Researchers at the University of Guelph analyzed 31 commercial melatonin supplements. Melatonin content ranged from 83% below to 478% above the labeled amount. Between lots of the same product it varied by as much as 465%. More than 71% of the supplements were not within 10% of their label claim. In eight of them (26%) they also found serotonin, at 1 to 75 micrograms (PubMed).

Cohen and colleagues, 2023. A research letter in JAMA analyzed 25 melatonin gummy products bought online. The melatonin in the products that contained it ranged from 1.3 mg to 13.1 mg per serving, and the actual amount ranged from 74% to 347% of the labeled quantity. Twenty-two of the 25 products (88%) were inaccurately labeled, and only 3 were within 10% of the declared amount. One product had no detectable melatonin but contained 31.3 mg of cannabidiol (CBD) (PMC).

Both studies tested particular products at one moment. They do not say anything about a specific product you might buy. What they show is that the amount on a supplement label is a claim, not a measurement. Some products advertise independent testing, and we have not evaluated those programs.

What We Do Not Know

The best dose and time to take it. NCCIH notes uncertainties about what dose to use and when to give it. The evidence behind the AASM’s recommendation is from a single dose, 2 mg, in older adults.
What long-term use does. NCCIH says the possible long-term side effects are unclear.
How a given product compares with its label, unless it has been measured.
Whether the small average effects matter to you. A study describes a group of people and does not tell you what will happen to you.

Questions

Does melatonin work for insomnia?

For chronic insomnia in adults, the AASM suggests not using it, on weak evidence, and the ACP strongly recommends CBT-I first. Pooled trials of people with primary sleep disorders show a small average benefit of about 7 minutes faster to fall asleep and about 8 minutes more sleep.

How much melatonin should I take?

We cannot give a dose. NCCIH says there are uncertainties about what dose to use and when to give it. In the 2013 meta-analysis, higher doses showed larger effects on total sleep time but not on sleep quality. Ask a healthcare provider, especially if you take medication.

Is melatonin safe to take every night?

The sources do not settle this. NCCIH says short-term use appears safe for most people and information on long-term safety is lacking.

Can children take melatonin?

NCCIH says parents should speak with a healthcare provider first, and that it is not known whether melatonin could affect hormonal development.

Sources Cited in This Guide

National Center for Complementary and Integrative Health, NIH. “Melatonin: What You Need To Know.” Last updated May 2024. Read September 19, 2026. NCCIH
Ferracioli-Oda E, Qawasmi A, Bloch MH. “Meta-analysis: melatonin for the treatment of primary sleep disorders.” PLoS One. 2013. PMID 23691095
Gholami F, et al. “Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials.” J Neurol. 2022. PMID 33417003
Poza JJ, et al. “Melatonin in sleep disorders.” Neurologia. 2022. PMID 36064286
Sateia MJ, et al. “Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline.” J Clin Sleep Med. 2017. Read September 19, 2026. PMID 27998379
“Combination treatment for chronic insomnia disorder in adults: an American Academy of Sleep Medicine clinical practice guideline.” J Clin Sleep Med. 2026, online April 13, 2026. Read September 19, 2026. DOI 10.1007/s44470-025-00038-8
Erland LA, Saxena PK. “Melatonin Natural Health Products and Supplements: Presence of Serotonin and Significant Variability of Melatonin Content.” J Clin Sleep Med. 2017. PMID 27855744
Cohen PA, et al. “Quantity of Melatonin and CBD in Melatonin Gummies Sold in the US.” JAMA. 2023. PMID 37097362

This guide is for information and is not medical advice. Talk to a healthcare provider about medication, pregnancy, medical conditions and persistent sleep problems.